This book provides a new edition and a complete study of the archive of Claudius Tiberianus, partially published in the eighth volume (Nos. 467-81) of the Michigan Papyri. It comprises 18 papyrus-letters, mostly written by Claudius Terentianus, an Egyptian enrolled in the Roman army, to his friend and patron Claudius Tiberianus, a veteran settled in Karanis (Fayum). These texts constitute an ancient archive, as they include the letters which were found together in a niche under the staircase of the house of Tiberianus at Karanis between 1924 and 1935, along with further texts, which emerged from the antiquities market. The old (but diehard) practice of splitting ancient archives by selling parts of them on the market produced the disastrous consequence of losing all information about the exact provenance of the texts. Furthermore, the lack of a scientific approach in most papyrological digs of the early twentieth century led the early excavators to discard most information about the archaeological context where the papyri were found. For all these reasons, subsequent scholars, including Strassi, had to laboriously reconstruct the history of the archive by relying on the information yielded by the texts alone. Etc. at BMCR